The Orioles also will place right-hander Steve Johnson on the disabled list with strained right lat muscle on Sunday before rosters are finalized.
McFarland, who pitched four scoreless innings in the Orioles’ 6-1 exhibition win over the State College of Florida on Friday, was told he was making the team after the game by Orioles manager Buck Showalter.
"I was doing some shoulder exercises in the training room and he came right up to me and said it straight up,” McFarland said. “There was no messing around or nothing. I shook his hand and said 'Thank you' and he said 'Congratualations,' and that it was awesome.
"I'm breaking with the team, I made the club,” McFarland added. “I'm so happy, I'm ecstatic. It's surreal. This is incredible. I can't really sum it up into words right now. It's a dream come true. Since 2007 when my career started, that's what I've been hoping for and it finally happened. I'm just so excited."
The Orioles selected McFarland with the 23rd pick of December’s Rule 5 draft after he went 16-8 with a 4.03 ERA at the Triple-A and Double-A levels in the Indians’ farm system last year.
The decision to keep McFarland, a 23-year-old sinkerballer, makes the team’s pitching staff all but complete. The Orioles will open the season with an eight-man bullpen. Right-hander Chris Tillman will come off the DL before his scheduled start on April 6.
Right-hander Jair Jurrjens, who was injured in Wednesday’s game, will avoid the DL and will likely be optioned to Triple-A Norfolk to continue gaining strength in his right knee. Left-hander Mark Hendrickson will also be optioned to Triple-A so he can continue to work on his new sidearm delivery. Both are signed to minor league deals.
Johnson, who was among the 13 starting rotation candidates this spring, can be activated from the disabled list on April 7 because his last outing was March 22 against the Rays in Port Charlotte.
“Obviously, I am disappointed," Johnson said. "I definitely wanted to start out healthy, either way, wherever I ended up. But I’ll take some time, rest it and try to get healthy."
Johnson said he hoped he could resume baseball activities in "a couple days."